I sold my house.  I paid my friend to buy 20 bitcoins.  He bought from a place called Tour.  From an exchange called crc.  This exchange is in the dark web space.  My friend says that the exchange has transferred bitcoins to its user.  But he can not transfer from the user to the wallet.  He has assured me that he has received the bitcoins.  But from its dark web user can not transfer it to the wallet.